dbcve.org
Usg 20w Vpn FirmwareOperating system · Zyxel

CVE-2023-33012

HIGH · 8.8 CVSS v3.1 Published 2023-07-17
Fix available
A fix is available. Upgrade to 5.37 or later.
See remediation →
93/100
Remediation priority · Urgent
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A command injection vulnerability in the configuration parser of the Zyxel ATP series firmware versions 5.10 through 5.36 Patch 2, USG FLEX series firmware versions 5.00 through 5.36 Patch 2, USG FLEX 50(W) series firmware versions 5.10 through 5.36 Patch 2, USG20(W)-VPN series firmware versions 5.10 through 5.36 Patch 2, and VPN series firmware versions 5.00 through 5.36 Patch 2, could allow an unauthenticated, LAN-based attacker to execute some OS commands by using a crafted GRE configuration when the cloud management mode is enabled.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A command injection vulnerability exists in the configuration parser of multiple Zyxel firewall series (ATP, USG FLEX, USG20W-VPN, VPN). An unauthenticated attacker on the LAN can execute arbitrary OS commands by sending a crafted GRE configuration when cloud management mode is enabled.

MitigationDisable cloud management mode if not required, apply vendor patches, and restrict LAN access to trusted users only.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Usg 20w Vpn FirmwareOperating system
Affected:>= 5.10, < 5.37
Usg 2200 Vpn FirmwareOperating system
Affected:>= 5.00, < 5.37
Usg Flex 100 FirmwareOperating system
Affected:>= 5.00, < 5.37
Usg Flex 100w FirmwareOperating system
Affected:>= 5.00, < 5.37
Usg Flex 200 FirmwareOperating system
Affected:>= 5.00, < 5.37
Usg Flex 50 FirmwareOperating system
Affected:>= 5.00, < 5.37
Usg Flex 500 FirmwareOperating system
Affected:>= 5.00, < 5.37
Usg Flex 50w FirmwareOperating system
Affected:>= 5.00, < 5.37

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the firewall model
    Access the device web interface or CLI and note the exact model name (e.g., USG Flex 50, USG 20W-VPN, USG 2200 VPN, ATP series).
    Affected if The model is one of: USG 20w VPN, USG 2200 VPN, USG Flex 100, USG Flex 100w, USG Flex 200, USG Flex 50, USG Flex 500, USG Flex 50w, or an ATP series variant.
  2. Check the installed firmware version
    In the web interface, go to Maintenance > Firmware or use the CLI command 'show system-info' to retrieve the firmware version.
    Affected if The firmware version is lower than 5.37 and falls within the affected range (e.g., 5.10 to 5.36 for USG 20w VPN, or 5.00 to 5.36 for other models).
  3. Verify if cloud management mode is enabled
    In the web interface, navigate to CONFIGURATION > Cloud Management or use the CLI to check the management mode status. Look for a setting indicating cloud management is active.
    Affected if Cloud management mode is enabled on the device.

The device is affected if it is a supported Zyxel model running firmware version 5.00 to 5.36 (or 5.10 to 5.36 for USG 20w VPN) AND cloud management mode is currently enabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.37 or later
Fixed in 5.37
Interim mitigation

Disable cloud management mode if not required, apply vendor patches, and restrict LAN access to trusted users only.

Recommended fix High confidence

Firmware version 5.37 or later for the specific USG model

  1. 1. Identify the exact USG model (e.g., USG 20w VPN, USG Flex 100, etc.) from the affected product list
  2. 2. Access the device web management interface or CLI
  3. 3. Check the current firmware version under System > Firmware or using 'show system info' command
  4. 4. Download firmware version 5.37 or later from the official Zyxel support website (www.zyxel.com/support) for your specific model
  5. 5. Upload the firmware file through the web interface (System > Firmware > Upload) or via CLI using the firmware upgrade command
  6. 6. Wait for the upgrade process to complete - do not power off the device
  7. 7. After reboot, verify the new firmware version is 5.37 or later
  8. 8. Confirm the cloud management mode setting as described in the vulnerability (disable if not needed)
Caveat Review Zyxel release notes for your model before upgrading; ensure backup of current configuration

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Usg 20w Vpn Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA3.0 h
19.0 hours of engineering $3,380
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,408.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2023-33012 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-33012 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data